When I look at the manual, starting around page 197 it describes the way you define the dial plan, which probably not by coincidence looks just like the way you define dial plans on a Cisco/Linksys adapter.
Somewhere in the config the dial plan for each line is something like this:
(1234;<+>567.;....;911S0)
It's list of digit patterms separated by semicolons. You need to add
988S0 to ths list, which means recognize 988 and put the call through immediately (zero second timeout). The patterns are evaluated in parallel so it doesn't matter where in the list it goes.This assumes that your carriers know what to do with 988. If not, thie should work, dialing the actual 800 number of the 988 provider instead:
<988S0:180027388255>If your dial plan still lets you dial local calls with seven digits (mine does) you might want to undo that if you care about being abie to call 988-XXXX numbers in your area code.
R's, John